Year Total 1970 1566000 1971 2337000 1972 3355000 1973 4260000 1974 4860000 1975 5219000 1976 6161000 1977 7038000 1978 7577000 1979 8722000 1980 10015000 1981 10855000 1982 10587000 1983 11500000 1984 10955000 1985 11698000 1986 12765000 1987 13036000 1988 13337000 1989 15302000 1990 17690000 1991 18839000 1992 20572000 1993 21356000 1994 24334000 1995 25479000 1996 25672000 1997 25676000 1998 26229000 1999 26610000 2000 27028000 2001 28287000 2002 28605000 2003 29254000 2004 31150000 2005 33159000 2006 35298000 2007 37117000 2008 36374000 2009 41332000 2010 45358000 2011 47857000 2012 51198000 2013 53127000 2014 57268000 2015 65361000 2016 82039000